1. Field of the Invention
The present invention relates to mixer taps, i.e. taps with a plurality of fluid inputs which are mixable to be ejected from one or more common outputs. For example, mixer taps are used on kitchen sinks to provide a single water supply with controllable temperature. The present invention is applicable to mixer taps having a pull-out or pull-down spray facility, i.e. where the or an additional fluid outlet is detachable from the main unit to give flexible user-directable flow.
2. Summary of the Prior Art
Mixer taps are well known. Typically, fluid input from a plurality of sources (usually hot and cold water supplies) is controllably conveyed to a mixing chamber, where the fluid is mixed and ejected through an output spout. Such mixer taps commonly use a single lever mixing valve to control the flow rate and temperature of the ejected water. Temperature is controlled by adjusting the ratio of hot to cold inputs received in the mixing chamber. A single lever mixing valve can control these two properties using a combination of rotational and tilting movements of an actuator operably connected to the control lever of the mixing valve. For example, the actuator (e.g. tap head) may be rotated to control temperature and tilted to control flow rate. This is conventional.
To give greater flexibility it is increasingly common to combine a side spray unit with the main mixer tap. Previously, separate side sprays were used, but when used with mixer taps these suffered from problems in efficiently delivering mixed water from the mixing chamber to the side spray. For example, one proposal incorporated an automatic diverter valve in the mixer tap to deflect water to a side spray when the side spray was operated. To fit in the mixer tap, the diverter valve was small, which meant that in time it was liable to become clogged with limescale and therefore reduce flow to the spray. By combining the side spray unit with the main tap, the problems caused by the diverter valve could be avoided.
In one combined proposal (known as a pull-out spray), a spray head is removably attached to the side of the tap beneath the mixing valve with a hose connecting the spray head to the valve. In another combined proposal (known as a pull-down spray), the main tap spout has a traditional goose neck configuration through which the tube that feeds the spray nozzle passes. The spray nozzle is removably attached to the mouth of the spout; when attached it operates as the main tap outlet, when detached (pulled down) it operates as a hand spray. Typically the connecting hose is longer than the spout to give flexibility of movement.